Service manual

Wells-Garnder Color Vector Monitor Guide
Page 57 of 73
Appendix B: Theory of Operation
THEORY OF OPERATION: Wells Gardner "Quadrascan" Color X-Y Monitor
CAUTION!!! LETHAL VOLTAGES ARE PRESENT IN THIS MONITOR, IF YOU
HAVE ANY DOUBTS ABOUT YOUR ABILITY DO NOT ATTEMPT TO REPAIR
YOUR MONITOR!!
The “Quadrascan” color X-Y display was designed and built by Wells Gardner Electronics Corp.
This display differs VERY LITTLE from the Electrohome G-05 Black and White X-Y monitor.
The only difference is that this monitor has three Z amplifiers to control three color guns. Refer
to the G-05 theory if there is any confusion on operating principles.
PINOUTS
Pin Description Notes
1. Red input 4.0V full on; 1.0V black level
2. Green input 4.0V full on; 1.0V black level
3. Blue input 4.0V full on; 1.0 black level
4. Red GND
5. Green GND
6. Blue GND
7. X input 16V P/P 2.5Kohms
8. Y input 12V P/P 2.5Kohms
9. Not Used
10. X GND
11. Y GND
12. Power GND
13. 25VRMS
14. Power GND
15. 25VRMS
LOW VOLTAGE POWER SUPPLY
The input voltage of 48 VAC from the game power supply enters through fuses F100 and F101.
Diodes D100 through D104 form a rectifier bridge that converts the AC input to an unfiltered